1. Field
This invention relates to apparatus for extending and retracting flexible sheet covers relative to the beds of automotive trucks to protect the load, e.g. to prevent loose material being transported from being blown away during travel.
2. State of the Art
Various arrangements of mechanisms have been proposed heretofore for moving a roller, on which a flexible cover sheet is rolled, back and forth over the bed of a truck from cover anchorage along one wall of the truck bed. Apparatus of this type, having one end of the cover sheet anchored along the forward wall of the truck bed at the cab of the truck, is shown by U.S. Pat. Nos. 3,549,198; 4,050,734; 4,082,347; and 4,341,416. The rollers are power operated and spring biased for tensioning the flexible cover sheet as it is unrolled from the roller and re-rolled on it. U.S. Pat. No. 4,225,175, shows a so-called "chip transport box" that apparently in Sweden is customarily carried on the bed of a truck or trailer. There, a side margin of the cover sheet is attached to a sidewall of the box for back and forth movement between the opposite side walls of such box. Several different arrangements are shown for tensioning the cover sheet and for clamping its end margins against disruption during travel.
3. Objective
A principal objective of the present invention is to provide for side-to-side covering of a truck bed by a relatively long cover sheet on a roller having simple and effective operative mechanism, there being a simple and effective sealing arrangement for the end margins of the cover sheet.